1. Field of the Invention
This invention relates to a local clock buffer (LCB) fabricated in a semiconductor. The LCB receives a global clock signal as input and implements a pulse width controller that is operationally coupled to the LCB and an output driver forming a ring oscillator. The output driver outputs a pulse width adjusted signal. The pulse width of the pulse width adjusted signal is adjustable by way of the pulse width controller and is related in frequency to the global clock signal. A second ring oscillator (also referred to as the nclk loop) can also be implemented to serve as the global clock signal. The pulse width controller can be used to precisely adjust the pulse width of the pulse width adjusted signal. A pulse width multiplier can be implemented to allow direct observation and measurement of the pulse width of the pulse width adjusted signal.
2. Description of Background
Before our invention local clock buffers (LCB) were used in semiconductor design to distribute a global clock signal to the many functional blocks, which comprise the semiconductor.
In high-speed designs it can be very important to characterize pulsed clocking to insure correct operation of the circuit. As such, current high-speed design test methods at LCB boundaries do not directly correlate with pulse width. In addition, pulse clocks can be more sensitive to logic failures and latch point failures can be caused by many more variables then just the pulse width.
As such, it is often difficult to separate these variables, and in particular to isolate, test, and use the LCB output signal pulse width as a way in which to characterize LCB performance. In addition, there are no ways in which to adjust or tune the LCB output signal pulse width.